"The mean purity of cocaine powder increased for the second year in a row after decreasing since 2005 (Table 10.8). The purity remains far below the levels seen in 2005 and almost half the level of 2003. Cocaine powder is commonly adulterated with benzocaine and levamisole.
"Given that the price of cocaine powder remained stable and purity increased slightly, there was a decrease in the purity-adjusted price of cocaine powder from £86.05 to £78.17 following a peak in 2009 (Table 10.10). Nevertheless, the price remains 42% higher than in 2003."


UK Focal Point on Drugs, "United Kingdom Drug Situation 2012 Edition: Annual Report to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA)" (London, England: UK Government, Department of Health, October 31, 2012), p. 184.